1. Technical Field
A liquid composition for treatment of stained fabric is disclosed. The composition may be an aqueous emulsion that includes a fatty alcohol as a stabilizer. The composition may also include one or more nonionic surfactants, detersive enzymes, borax, cleaning agents, fragrances, pH adjusting agents, thickeners, and preservative. Long term stability and stain removal performance of the composition are also disclosed.
2. Description of the Related Art
Conventional laundering processes using automatic washing machines are well known in the art. Those processes, when using commercial detergents, are generally effective in removing everyday stains from laundry items but are sometimes insufficient to remove tough stains such as those of used motor oil, blood, coffee, ink, dirt, grass and wine, etc. In order to effectively remove such tough stains, it is desirable to pretreat (or prespot) the stains before the laundry items are washed. In an exemplary pretreatment, a pretreatment composition is delivered to the stains and the formulation-treated stains are rubbed or scrubbed so that the stains are loosened, dislodged, or dissolved. Thereafter, the treated stains are effectively removed by one of the conventional laundering processes.
Ordinary laundry pretreatment compositions for loosening tough stains on fabrics generally contain considerable amounts of oxidant and/or bleach components. The bleach components may be ozone, hypochlorides, halogen oxides, peroxides or other conventional bleaching agents. The bleaching components may also be bleach catalysts that facilitate oxidation reactions by oxygen in the air. One problem associated with the bleaching components is that they may not be compatible with other essential ingredients of the composition, including enzymes. Moreover, the bleach components may also cause discoloration of delicate fabrics if not timely rinsed with water. Therefore, bleach components may need to be excluded in some pretreatment compositions.
Use of enzymes in cleaning compositions for stain removal is also known in the art. For example, when used in laundry detergent compositions enzymes may degrade a wide variety of soils or stains that are deposited on or embedded within fabrics or otherwise change the properties of the same. In the case of dish washing detergents, enzymes have been found to degrade various fats and oils, proteins, starches and the like which are adhered to the surfaces of dishes. In general, enzymes in cleaning compositions function to loosen soils and stains on a surface and render them more readily removed during a washing process.
Moreover, as recognized in U.S. Pat. No. 4,111,855, “the formulation of enzyme-containing liquid detergent compositions is a very delicate task due to the rapid decrease of the enzymatic activity in aqueous medium during storage” (col. 1, lines 39-42). Although enzymes may be stabilized in aqueous cleaning compositions by a variety of methods, the formation of an enzyme-containing emulsion has been found to substantially prevent enzyme degradation in pretreatment compositions. The emulsion may include one or more nonionic surfactants, detersive enzymes, borax, fragrances, pH adjusting agents, thickeners, preservative, and water.
Nevertheless, in order to preserve the detergent activity of the enzymes, such emulsions must be themselves stable during storage. In some countries, including U.S., product stability is evaluated at 10° C. (low temperature storage), 20-25° C. (ambient temperature storage), and 38° C. (elevated temperature storage). In other countries, however, stability is evaluated under ambient and elevated temperatures. In any event, some enzyme-containing emulsions fail to provide sufficient stability at one or all of those temperatures, resulting in decreased soil and/or stain removal performance of same. For example, an aqueous emulsion containing 0.2% enzyme, a nonionic surfactant blend of 2% isotrideceth-8, 2% ethoxylated undecyl alcohol, and 2% ethoxylated (3 Moles) isotridecanol, 89.25% water, and other ingredients including borax, pH adjusting agents, thickeners, preservatives, and fragrance, is found to exhibit phase separation within two days at both low and ambient storage temperatures.
Hence, there is a need for an enzyme-containing liquid laundry pretreatment composition with improved long term stability under low, ambient, and/or elevated storage temperatures. Moreover, there is a need for a stable enzyme-containing pretreatment composition that that performs comparably to existing pretreatment compositions.